In the related art, there are wearable image display devices that are worn by and display images to a user. Head-mounted displays (HMD) are examples of such devices. HMDs are generally divided into monocular and biocular devices and are further classified into non-see-through type devices and see-through type devices. In non-see through type devices, vision is secured in the movement space in which the user is actually moving (that is, real space). In see-through type devices, each eye of the user is masked (that is, completely covered) and images linked to the real space are displayed.
Recently, technologies have been proposed for game devices configured as simulation systems that display predetermined images on such an HMD (for example, JP-A-2015-150063). In such technologies, the field-of-view of the user in virtual space is supported, thereby enhancing the effectiveness and immersiveness of the simulated world.